The invention relates to an apparatus for the induction hardening of workpieces rotatable about the rotation axis and in particular crankshaft bearings in the rotary process. It is conventional practice in this respect to heat different parts of the workpiece surface by means of differently shaped inductors, for which purpose the workpiece is horizontally secured and rotates. These differently shaped inductors make it possible to produce varying hardened layers or action depths.
It is necessary to juxtapose these differently shaped inductors in an inductor magazine and successively convey them to the workpiece for use. However, this involves a very complicated apparatus. Inter alia, it must be possible to automatically couple the inductors to the transformer terminals.
It is also known that these hardening plants comprise the most varied equipment, which successively receive the workpieces to be hardened in the clamping device, bring them into the heating position at the inductors, rotate them for hardening purposes, immerse them in a quenching bath or place them in a quenching shower and then pass them on from the plant for further treatment.
According to the prior art, at least 1 minute is required for the aforementioned replacement of the inductors from the magazine, because it is necessary to perform relatively long travel movements, carry out pivotal movements, as well as the stopping and rotation of the parts to be hardened (German Pat. Nos. 2,332,832 and 2,334,126).